What is the magnitude of the magnetic field?

[mba444]

What is the magnitude of the magnetic field??

Homework Statement

A small rectangular coil composed of 37 turns
of wire has an area of 36 cm2 and carries a
current of 0.8 A. When the plane of the coil
makes an angle of 18◦ with a uniform magnetic
field, the torque on the coil is 0.07 Nm.
What is the magnitude of the magnetic
field? Answer in units of T.

Homework Equations

Torque = n*i*A*B*sin(theta)
B= torque/(n*i*A*sin(theta))
n is the number of turns

The Attempt at a Solution

what i did is that i plugged all the given values .. but i keep get the wrong answer .. i don't know where is my mistake

thanx in advance

 

[rock.freak667]

Did you convert the area to m²?

 

[jix]

theta is the angle made between the normal to the coil to the magnetic field. Think about it, if the coil is parallel to the magnetic field (theta = 0), the torque is maximum (the forces on the wires are directly opposite), as opposed to if you used sin 0 = 0, that is torque = 0. So you have to use sin 72 or cos 18 in the equation.

I don't even know if that's the problem, but I hope it helps.